The number of animals used in medical experiments increased in 2005.
Most of the experiments involved mice, rats and other rodents and most of the rest were on fish and birds.
A report published by the government on Monday showed that last year just over 2.91 million tests were performed, which is 2% more than in 2004.
Although the number of animals tested on is up on last year, there are still fewer experiments on animals taking place than there were 30 years ago.
Scientists use animals to test for new drugs and ways of treating people.
Home Office Minister Joan Ryan said: "Animal research and testing has played a part in almost every medical breakthrough of the last century.
"It has saved hundreds of millions of lives worldwide."
But some animal welfare groups think there are other ways of testing medicines for humans.
Alistair Currie, campaign director for the British Union for the Abolition of Vivisection, said: "Sadly, it's no surprise that numbers have gone up again. This government has no grasp of the problem of animal experimentation and no strategy to bring numbers down."